1. Field of the Invention
The present embodiments relate to a thin film transistor, a method for preparing the same and a flat panel display employing the same, and more particularly, to a this film transistor having improved charge mobility by overcoming a hysteresis characteristic problem, a method for preparing the same and a flat panel display employing the thin film transistor.
2. Description of the Related Art
A thin film transistor (TFT) used in a flat panel display device such as, for example, a liquid crystal display device, an organic light-emitting device, or an inorganic light-emitting device, is used as a switching element for controlling the operation of each pixel and a driving element for driving the pixel.
Such a TFT includes a semiconductor layer having source region and a drain region, and a channel region formed between the source/drain regions, a gate electrode insulated from the semiconductor layer and positioned on a region corresponding to the channel region, and source/drain electrodes contacting the source/drain regions, respectively.
Since the source/drain electrodes are generally made of a metal having a low work function for facilitating the flow of charges, contact resistance increases at a region where the metal and the semiconductor layer contact each other, resulting in a deterioration of device characteristics and increasing power consumption.
Recently, research into an organic thin film transistor has been actively conducted because it is advantageous in that it comprises an organic semiconductor layer. Since the organic semiconductor layer can be formed at a low temperature, use of a plastic substrate has become possible.
To improve electrical performance of the organic thin film transistor, e.g., a driving voltage, a thin film transistor comprising a buffer layer between a source/drain electrode and an organic semiconductor layer or a self-assembly monolayer between a gate insulating layer and an organic semiconductor layer has been proposed, as described in Japanese Patent Laid-open Publication No. 2004-103905.
However, known organic thin film transistors have not hitherto been suited to actual applications due to hysteresis characteristics. Accordingly, it would be highly desirable to develop thin film transistors having satisfactory operational stability.